1. Field of the Invention
The present invention relates to an electrically driven pump device and, more particularly, to an electrically driven pump device having an improved air passage structure.
2. Related Art
A conventional washer device for vehicles has, as shown in FIG. 6, a washer pump device 40, which jets washer fluid of a washer tank from a washer nozzle. The washer pump device 40 is driven electrically by a direct current (d.c.) motor 42 accommodated within a motor housing 41. Specifically, an impeller 45 is accommodated within a pump housing 44 and is coupled with a rotary shaft 43 of the motor 42 to rotate with the rotary shaft 43. An airpassage 46 is provided between the motor housing 41 and the pump housing 44 to maintain the pressure uniformly between the inside and outside of the motor housing 44, thereby ensuring normal operation of the washer pump device 40. The air passage 46 is formed in a labyrinth shape (L-shape) to restrict rain and water splash from entering into the motor housing 41.
However, water is still likely to enter into the inside of the motor 42, because water rebounds on air passage walls and moves upward when the water hits the air passage 46 at high speeds from the bottom side. This will occur more often in a vehicle which has the washer pump device 40 at the front side of a vehicle front tire, because the tire generates water splash when the vehicle runs over puddles.